How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Rick Your Own Question
Rick
Rick, General Contractor
Category: Home Improvement
Satisfied Customers: 19520
Experience:  Licensed construction supervisor with 35+ yrs. experience.
94766
Type Your Home Improvement Question Here...
Rick is online now
A new question is answered every 9 seconds

I'm building a basketball court that is sunken into the

Customer Question

Hi, I'm building a basketball court that is sunken into the ground due to a sloping back yard. On 2 sides of the court slab the dirt is 3ft high and the contractor built forms on 1 side and the other side is a dirt wall that was basically carved out when
they dug the area. Essentially he is going to pour concrete between the form and the cut out earth. The earth wall is really hard because we have clay soil so it is not soft or loose. The retaining wall will be 3ft high, 8" wide, has #5 rebar going horizontal
and #3 vertically. The wall is not cantilever but when they pour concrete for the slab (bball court) they will also pour the walls so everything will be one massive concrete structure. I don't want it to cave in on me in a few years so is this enough to hold
the dirt back? I live in Dallas and we have clay soil which is hard as a rock but when wet expands. They did not dig a footer under the wall because technically the slab will be the footer. Also no beams or piers used just rebar and then they will pour concrete.
Please help!! Thank you
Submitted: 1 year ago.
Category: Home Improvement
Expert:  Rick replied 1 year ago.

My primary concern would be the expansive soil. Your contractor's approach is ok with a few modifications. First an explanation, expansive soil on a flat grade or one that slopes away from a wall would tend to expand vertically not exerting much force against the wall. Looks like your grade is pretty flat. But I don't like the jagged edge of soil on the back of the wall pour. I'd suggest at a minimum the soil be cut smooth so any vertical soil movement has nothing to "grab". A smooth plywood form on the back side would be better. Beyond that given the grade behind the wall and the fairly short height of the wall you should be OK.

Customer: replied 1 year ago.
you don't think the pressure of the dirt on the wall over time will push the wall over? There's no footing other than the 4" slab but that will all be poured at the same time so it'll be one structure. Don't know if that helps any on the wall or not. The grade is fairly flat as you mentioned. We have clay soil here in Dallas and it's fairly dry all the time not much rain so soil doesn't shift but clay expands when wet so that can put pressure over time. Do you know why anyone would pour against the jagged earth instead of putting plywood or a form? As you mentioned you don't like that because vertical earth has nothing to grab on to.
Expert:  Rick replied 1 year ago.

You don't need a footing because the wall isn't support a load (like a house foundation). Like I said before when the grade is flat the expansive pressure tends to be vertical not horizontal (towards the wall). The re-bar in the wall is an appropriate measure to strengthen the wall. The only reason I can think of for not forming up the wall on both sides is for the contractor to save money.